Adamite

Adamite is a zinc arsenate prized by collectors for its bright, glowing yellow-green crystals, most famously from the Ojuela mine in Mexico.

Identifying adamite

Adamite forms sparkling druses of small wedge-shaped crystals, typically vivid yellow-green to honey-yellow, on a brown limonite matrix; many specimens fluoresce a strong lime-green under ultraviolet light. Rarer varieties include purple cobaltoan adamite and green cuproadamite, coloured by traces of cobalt and copper.

The Ojuela connection

The Ojuela mine at Mapimí, Durango, Mexico is the classic locality, producing brilliant yellow-green adamite druses on limonite that set the standard for the species. Adamite also comes from Lavrion in Greece, Tsumeb in Namibia and other oxidised zinc deposits.

For collectors

Bright, lustrous yellow-green druses with strong fluorescence are the prize, along with the scarcer purple and green cobalt- and copper-bearing varieties.